Christopher Black, 25, whose black-and-white cat Smudge was one of the Weston victims, had his pet put down after it started having fits and crying out in pain.

He said: 'I don't think it is an accident because it is too much of a coincidence for this many cats to die in one area.

Bridgwater is just around the corner from Weston, so it could well be the same person doing it.'

He added: 'I was in complete shock and I'm a grown man but I cried for at least three days over it.

'I find it horrible to think anybody could do that kind of thing to a loveable little animal. There must be something seriously wrong with anybody who gets their kicks from poisoning cats.'

Another pet owner from Weston, whose cat Tom died two weeks ago, said: 'Four cats have died from my block of flats, all under six years old.

My cat meant so much to me and everyone is upset about what has happened.'

Rebecca Martin, veterinary surgeon at the town's Green Pastures Veterinary Centre, said: 'We have seen about four or five cats here and none of those has been successfully treated.

'By the time we see them they are usually collapsed. Because the kidneys are used to flush toxins out of the body they are usually suffering from kidney failure and there is very little we can do to reverse those effects.

'We have had to advise they be put to sleep on humane grounds.'

The RSPCA said its investigation into the deaths was split between searching for a malicious psycho-path and an innocent source of the chemical, such as a breaker's yard.

There is also the possibility the latest spate of killings may have been committed by a second killer imitating what happened in Bridgwater in August.

The Animal Welfare Act 2006 states that anyone found guilty of causing unnecessary suffering to an animal can face a maximum six-month prison sentence and a £20,000 fine.

Avon and Somerset Police said it was supporting the RSPCA in its investigations.